Genomic Clustering Facilitates Nuclear Processing of Suboptimal Pri-miRNA Loci.
Mol Cell
; 78(2): 303-316.e4, 2020 04 16.
Article
em En
| MEDLINE
| ID: mdl-32302542
ABSTRACT
Nuclear processing of most miRNAs is mediated by Microprocessor, comprised of RNase III enzyme Drosha and its cofactor DGCR8. Here, we uncover a hidden layer of Microprocessor regulation via studies of Dicer-independent mir-451, which is clustered with canonical mir-144. Although mir-451 is fully dependent on Drosha/DGCR8, its short stem and small terminal loop render it an intrinsically weak Microprocessor substrate. Thus, it must reside within a cluster for normal biogenesis, although the identity and orientation of its neighbor are flexible. We use DGCR8 tethering assays and operon structure-function assays to demonstrate that local recruitment and transfer of Microprocessor enhances suboptimal substrate processing. This principle applies more broadly since genomic analysis indicates suboptimal canonical miRNAs are enriched in operons, and we validate several of these experimentally. Proximity-based enhancement of suboptimal hairpin processing provides a rationale for genomic retention of certain miRNA operons and may explain preferential evolutionary emergence of miRNA operons.
Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Ligação a RNA
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Genômica
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MicroRNAs
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Ribonuclease III
Limite:
Humans
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article